using System;
using System.Collections;
using System.Collections.Generic;

namespace LightCAD.Three
{
    public class Matrix3 : IIOArray
    {
        #region scope properties or methods
        //private static Matrix3 _m3 = new Matrix3();
        private static Matrix3Context getContext()
            => ThreadContext.getCurrThreadContext().Matrix3Ctx;
        #endregion

        #region Properties

        public double[] elements;

        #endregion

        #region constructor
        public Matrix3()
        {
            this.elements = new double[] {
                    1, 0, 0,
                    0, 1, 0,
                    0, 0, 1
                };
        }
        #endregion

        #region methods
        public Matrix3 set(double n11, double n12, double n13, double n21, double n22, double n23, double n31, double n32, double n33)
        {
            double[] te = this.elements;
            te[0] = n11; te[1] = n21; te[2] = n31;
            te[3] = n12; te[4] = n22; te[5] = n32;
            te[6] = n13; te[7] = n23; te[8] = n33;
            return this;
        }
        public Matrix3 identity()
        {
            this.set(
                1, 0, 0,
                0, 1, 0,
                0, 0, 1
            );
            return this;
        }
        public Matrix3 copy(Matrix3 m)
        {
            double[] te = this.elements;
            double[] me = m.elements;
            te[0] = me[0]; te[1] = me[1]; te[2] = me[2];
            te[3] = me[3]; te[4] = me[4]; te[5] = me[5];
            te[6] = me[6]; te[7] = me[7]; te[8] = me[8];
            return this;
        }
        public Matrix3 extractBasis(Vector3 xAxis, Vector3 yAxis, Vector3 zAxis)
        {
            xAxis.setFromMatrix3Column(this, 0);
            yAxis.setFromMatrix3Column(this, 1);
            zAxis.setFromMatrix3Column(this, 2);
            return this;
        }
        public Matrix3 setFromMatrix4(Matrix4 m)
        {
            double[] me = m.elements;
            this.set(
                me[0], me[4], me[8],
                me[1], me[5], me[9],
                me[2], me[6], me[10]
            );
            return this;
        }
        public Matrix3 multiply(Matrix3 m)
        {
            return this.multiplyMatrices(this, m);
        }
        public Matrix3 premultiply(Matrix3 m)
        {
            return this.multiplyMatrices(m, this);
        }
        public Matrix3 multiplyMatrices(Matrix3 a, Matrix3 b)
        {
            double[] ae = a.elements;
            double[] be = b.elements;
            double[] te = this.elements;
            double a11 = ae[0], a12 = ae[3], a13 = ae[6];
            double a21 = ae[1], a22 = ae[4], a23 = ae[7];
            double a31 = ae[2], a32 = ae[5], a33 = ae[8];
            double b11 = be[0], b12 = be[3], b13 = be[6];
            double b21 = be[1], b22 = be[4], b23 = be[7];
            double b31 = be[2], b32 = be[5], b33 = be[8];
            te[0] = a11 * b11 + a12 * b21 + a13 * b31;
            te[3] = a11 * b12 + a12 * b22 + a13 * b32;
            te[6] = a11 * b13 + a12 * b23 + a13 * b33;
            te[1] = a21 * b11 + a22 * b21 + a23 * b31;
            te[4] = a21 * b12 + a22 * b22 + a23 * b32;
            te[7] = a21 * b13 + a22 * b23 + a23 * b33;
            te[2] = a31 * b11 + a32 * b21 + a33 * b31;
            te[5] = a31 * b12 + a32 * b22 + a33 * b32;
            te[8] = a31 * b13 + a32 * b23 + a33 * b33;
            return this;
        }
        public Matrix3 multiplyScalar(double s)
        {
            double[] te = this.elements;
            te[0] *= s; te[3] *= s; te[6] *= s;
            te[1] *= s; te[4] *= s; te[7] *= s;
            te[2] *= s; te[5] *= s; te[8] *= s;
            return this;
        }
        public double determinant()
        {
            double[] te = this.elements;
            double a = te[0], b = te[1], c = te[2],
                d = te[3], e = te[4], f = te[5],
                g = te[6], h = te[7], i = te[8];
            return a * e * i - a * f * h - b * d * i + b * f * g + c * d * h - c * e * g;
        }
        public Matrix3 invert()
        {
            double[] te = this.elements;
            double n11 = te[0], n21 = te[1], n31 = te[2],
               n12 = te[3], n22 = te[4], n32 = te[5],
               n13 = te[6], n23 = te[7], n33 = te[8],
               t11 = n33 * n22 - n32 * n23,
               t12 = n32 * n13 - n33 * n12,
               t13 = n23 * n12 - n22 * n13,
               det = n11 * t11 + n21 * t12 + n31 * t13;
            if (det == 0) return this.set(0, 0, 0, 0, 0, 0, 0, 0, 0);
            double detInv = 1 / det;
            te[0] = t11 * detInv;
            te[1] = (n31 * n23 - n33 * n21) * detInv;
            te[2] = (n32 * n21 - n31 * n22) * detInv;
            te[3] = t12 * detInv;
            te[4] = (n33 * n11 - n31 * n13) * detInv;
            te[5] = (n31 * n12 - n32 * n11) * detInv;
            te[6] = t13 * detInv;
            te[7] = (n21 * n13 - n23 * n11) * detInv;
            te[8] = (n22 * n11 - n21 * n12) * detInv;
            return this;
        }
        public Matrix3 transpose()
        {
            double tmp;
            double[] m = this.elements;
            tmp = m[1]; m[1] = m[3]; m[3] = tmp;
            tmp = m[2]; m[2] = m[6]; m[6] = tmp;
            tmp = m[5]; m[5] = m[7]; m[7] = tmp;
            return this;
        }
        public Matrix3 getNormalMatrix(Matrix4 matrix4)
        {
            return this.setFromMatrix4(matrix4).invert().transpose();
        }
        public Matrix3 transposeIntoArray(double[] r)
        {
            double[] m = this.elements;
            r[0] = m[0];
            r[1] = m[3];
            r[2] = m[6];
            r[3] = m[1];
            r[4] = m[4];
            r[5] = m[7];
            r[6] = m[2];
            r[7] = m[5];
            r[8] = m[8];
            return this;
        }
        public Matrix3 setUvTransform(double tx, double ty, double sx, double sy, double rotation, double cx, double cy)
        {
            double c = JMath.cos(rotation);
            double s = JMath.sin(rotation);
            this.set(
                sx * c, sx * s, -sx * (c * cx + s * cy) + cx + tx,
                -sy * s, sy * c, -sy * (-s * cx + c * cy) + cy + ty,
                0, 0, 1
            );
            return this;
        }
        public Matrix3 scale(double sx, double sy)
        {
            var _m3 = getContext()._m3;
            this.premultiply(_m3.makeScale(sx, sy));
            return this;
        }
        public Matrix3 rotate(double theta)
        {
            var _m3 = getContext()._m3;
            this.premultiply(_m3.makeRotation(-theta));
            return this;
        }
        public Matrix3 translate(double tx, double ty)
        {
            var _m3 = getContext()._m3;
            this.premultiply(_m3.makeTranslation(tx, ty));
            return this;
        }
        public Matrix3 makeTranslation(double x, double y)
        {
            this.set(
                1, 0, x,
                0, 1, y,
                0, 0, 1
            );
            return this;
        }
        public Matrix3 makeRotation(double theta)
        {
            // counterclockwise
            double c = JMath.cos(theta);
            double s = JMath.sin(theta);
            this.set(
                c, -s, 0,
                s, c, 0,
                0, 0, 1
            );
            return this;
        }
        public Matrix3 makeScale(double x, double y)
        {
            this.set(
                x, 0, 0,
                0, y, 0,
                0, 0, 1
            );
            return this;
        }
        public bool equals(Matrix3 matrix)
        {
            double[] te = this.elements;
            double[] me = matrix.elements;
            for (int i = 0; i < 9; i++)
            {
                if (te[i] != me[i]) return false;
            }
            return true;
        }
        public bool equals(IIOArray obj) => equals(obj as Matrix3);
        public Matrix3 fromArray(double[] array, int offset = 0)
        {
            for (int i = 0; i < 9; i++)
            {
                this.elements[i] = array[i + offset];
            }
            return this;
        }
        IIOArray IIOArray.fromArray(double[] array, int offset)
        {
            return fromArray(array, offset);
        }
        public double[] toArray(double[] array = null, int offset = 0)
        {
            if (array == null) array = new double[9];
            double[] te = this.elements;
            array[offset] = te[0];
            array[offset + 1] = te[1];
            array[offset + 2] = te[2];
            array[offset + 3] = te[3];
            array[offset + 4] = te[4];
            array[offset + 5] = te[5];
            array[offset + 6] = te[6];
            array[offset + 7] = te[7];
            array[offset + 8] = te[8];
            return array;
        }
        public Matrix3 clone()
        {
            return new Matrix3().fromArray(this.elements);
        }


        #endregion

    }
}
